This invention relates to multilamp photoflash arrays and more particularly to multilamp photoflash arrays having readily visible means for identifying a flashed lamp.
Flashed-lamp indicators are used in high-voltage photoflash arrays to notify the user when the lamps have been flashed. In multiple lamp array type flash units, such as the Flip Flash and Super 10 arrays, spots of green or blue and heat-shrinkable film have been operatively associated with the lamps and located so as to be visible from the rear of the array. The heat generated by flashing of the lamp causes the film to melt and shrink back out of view exposing a different color to indicate the associated lamp has been flashed.
U.S. Pat. No. 3,609,331 discloses the use of a volatile dye spot on the surface of a flashlamp in a flashcube. The volatile dye spot vaporizes upon flashing of a lamp and condenses on the inside surface of the flashcube cover to define a noticeable colored area thereon. Upon prolonged aging of the product or upon prolonged exposure of the product to temperatures in excess of normal room temperature, the dye in the indicator spot gradually diffuses through the lacquer coating of the flashlamp. This diffusion of the dye causes the lacquer coating on the flashlamp to discolor. Such premature discoloration of the lamp lacquer results in off-color photographs.